Currently, refrigerated cabinets such as refrigerators and/or freezers, generally employ a single vapor-compression circuit to cool or maintain the temperature of the refrigerated cabinet. Typically, the refrigeration circuit uses a refrigerant or coolant gas which is cycled through the refrigeration circuit. During the cooling process, the refrigerant or coolant gas is compressed in a compressor unit causing the coolant to become hot. The heat generated by the aforementioned compression is then removed generally by passing the compressed gas through a water or air cooled condenser coil. The cooled, condensed liquid is then allowed to rapidly expand into an evaporating coil where the expanded gas becomes much colder, thus cooling the coil and the cabinet around which, or within which, the evaporating coil is placed.
Refrigerated cabinets employing vapor-compression circuits or systems similar to the circuit or system described above, are typically designed to cycle the vapor-compression circuit or system on and off in order to hold or maintain the cabinet temperature at a desired setting. Oftentimes, the aforementioned on and off cycling of the vapor-compression circuit or system may cause strain on the system's mechanical components such as the compressor. This cycling may also cause temperature fluctuations within the cabinet, and hence, air pressure fluctuations, within the cabinet. These temperature fluctuations often times cause undesired frost formation within the cabinet due to the pressure differential between the interior of the refrigerated cabinet and the outside environment, as a result of the varying cabinet air temperatures.
One current method for reducing the likelihood of the above-described temperature fluctuations includes adding a liquid refrigeration bypass circuit to the vapor-compression circuit. The bypass circuit allows for a portion of the liquid refrigerant or coolant to circumvent or bypass the evaporator, thus modulating the refrigerant or coolant flow capacity into the evaporator. This modulation of the flow of the liquid refrigerant or coolant into the evaporator causes the interior refrigerated cabinet temperature to be more stable thereby causing the air pressure within the cabinet to be more stable. Moreover, the aforementioned method allows for the compressor to run continuously and not cycle on and off.
The aforementioned method for addressing temperature fluctuation with refrigerated cabinets has drawbacks however. Due to the bypass circuit, the compressor runs constantly, causing the refrigerated cabinet to consume more energy than a refrigerated cabinet that employs a compressor that cycles on and off. Moreover, due to the constant operation of the compressor, operational noise levels of the refrigerated cabinet are increased.
Accordingly, there is a need in the art to provide a cooling circuit apparatus and method for use with refrigerated cabinets and the like, that allows for efficient, precise temperature control. Also, there is a further need for a cooling circuit apparatus and method for use with refrigerated cabinets that have a refrigerant or coolant bypass feature that may be activated and inactivated as desired.